Multilayer capacitor

Abstract

A multilayer capacitor includes: a body including dielectric layers and internal electrodes alternately disposed therein; and external electrodes disposed on the body and connected to the internal electrodes. The internal electrodes include a first internal electrode and a second internal electrode. A thickness of the second internal electrode is less than a thickness of the first internal electrode, and an area fraction of ceramics included in the first internal electrode with respect to the first internal electrode is greater than that of ceramics included in the second internal electrode with respect to the second internal electrode.

What is claimed is: 
     
       1. A multilayer capacitor comprising:
 a body including dielectric layers and internal electrodes alternately disposed therein; and 
 external electrodes disposed on the body and connected to the internal electrodes, respectively, 
 wherein the internal electrodes include a first internal electrode and a second internal electrode, a thickness of the second internal electrode being less than a thickness of the first internal electrode, and 
 an area fraction of ceramics included in the first internal electrode with respect to the first internal electrode is greater than that of ceramics included in the second internal electrode with respect to the second internal electrode. 
 
     
     
       2. The multilayer capacitor of  claim 1 , wherein in a cross-sectional of the multilayer capacitor, the area fracture of the ceramics included in the first internal electrode is 1 to 5 area % of the first internal electrode, and the area fracture of the ceramics included in the second internal electrode is 0.5 area % or less of the second internal electrode. 
     
     
       3. The multilayer capacitor of  claim 1 , wherein 1.05≤t 1 /t 2 ≤1.6 in which t 1  is the thickness of the first internal electrode and t 2  is the thickness of the second internal electrode. 
     
     
       4. The multilayer capacitor of  claim 1 , wherein the thickness of the first internal electrode is 0.2 to 1.0 μm, and the thickness of the second internal electrode is 0.14 to 0.95 μm. 
     
     
       5. The multilayer capacitor of  claim 1 , wherein a thickness of the dielectric layer is 0.14 to 0.95 μm. 
     
     
       6. The multilayer capacitor of  claim 1 , wherein the first internal electrode is made of a conductive paste having a sintering temperature lower than that of a conductive paste for making the second internal electrode. 
     
     
       7. The multilayer capacitor of  claim 1 , wherein the first and second internal electrodes are made of conductive pastes including conductive metal powder particles and ceramic powder particles, and
 an average particle size of the conductive metal powder particles included in the conductive paste for making the first internal electrode is smaller than that of the conductive metal powder particles included in the conductive paste for making the second internal electrode. 
 
     
     
       8. The multilayer capacitor of  claim 1 , wherein the first internal electrode is made of a conductive paste including conductive metal powder particles and ceramic materials, and an average particle size of the conductive metal powder particles is 100 nm or less. 
     
     
       9. The multilayer capacitor of  claim 1 , wherein the first internal electrode includes a Ni alloy alloyed with one or more materials selected from the group consisting of Cu, Si, and Al. 
     
     
       10. The multilayer capacitor of  claim 1 , wherein the second internal electrode includes a Ni alloy alloyed with one or more materials selected from the group consisting of W, Cr, and Co. 
     
     
       11. The multilayer capacitor of  claim 1 , wherein the first internal electrode includes a Ni alloy different from a Ni alloy included in the second internal electrode. 
     
     
       12. The multilayer capacitor of  claim 1 , wherein the second internal electrode is made of a conductive paste including conductive metal powder particles and ceramic powder particles, and the conductive metal powder particles are coated with sulfur (S) or carbon (C). 
     
     
       13. The multilayer capacitor of  claim 1 , wherein the second internal electrode includes a Ni grain, ceramics distributed in the Ni grain, a first coating layer surrounding the Ni grain, and second coating layers surrounding the ceramics. 
     
     
       14. The multilayer capacitor of  claim 13 , wherein each of the first and second coating layers includes one or more materials selected from the group consisting of Ag, Au, Zn, Sn, In, Al, Bi, Sb, Ge, and Te. 
     
     
       15. The multilayer capacitor of  claim 1 , wherein the number of first internal electrodes is two or more, and
 the second internal electrode is disposed between the two or more first internal electrodes. 
 
     
     
       16. The multilayer capacitor of  claim 1 , wherein the first and second internal electrodes are alternately disposed with respective dielectric layers interposed therebetween, and are alternately exposed through both end surfaces of the body, respectively. 
     
     
       17. A multilayer capacitor comprising:
 a body including dielectric layers and internal electrodes alternately disposed therein; and 
 external electrodes disposed on the body and connected to the internal electrodes, respectively, 
 wherein the internal electrodes include a first internal electrode and a second internal electrode having a thickness lower than that of the first internal electrode, and 
 among the first and second internal electrodes, only the second internal electrode includes a Ni grain, ceramics distributed in the Ni grain, a first coating layer surrounding the Ni grain, and second coating layers surrounding the ceramics. 
 
     
     
       18. The multilayer capacitor of  claim 17 , wherein each of the first and second coating layers includes one or more materials selected from the group consisting of Ag, Au, Zn, Sn, In, Al, Bi, Sb, Ge, and Te. 
     
     
       19. The multilayer capacitor of  claim 17 , wherein the first internal electrode does not include the first and second coating layers. 
     
     
       20. A multilayer capacitor comprising:
 a body including a first dielectric layer and first and second internal electrodes connected to each other by the first dielectric layer; and 
 first and second external electrodes disposed on the body and connected to the first and second internal electrodes, respectively, 
 wherein a thickness of the second internal electrode is less than a thickness of the first internal electrode, and 
 the first internal electrode is made of a first conductive paste having a sintering temperature lower than that of a second conductive paste for making the second internal electrode. 
 
     
     
       21. The multilayer capacitor of  claim 20 , wherein the first internal electrode includes a first Ni alloy alloyed with one or more materials selected from the group consisting of Cu, Si, and Al, and
 the second internal electrode includes a second Ni alloy alloyed with one or more materials selected from the group consisting of W, Cr, and Co. 
 
     
     
       22. The multilayer capacitor of  claim 20 , wherein the second internal electrode is made of a conductive paste including conductive metal powder particles and ceramic powder particles, and the conductive metal powder particles are coated with sulfur (S) or carbon (C). 
     
     
       23. The multilayer capacitor of  claim 20 , wherein the second internal electrode includes a Ni grain, ceramics coated with second coating layers and distributed in the Ni grain, and a first coating layer surrounding the Ni grain. 
     
     
       24. The multilayer capacitor of  claim 23 , wherein each of the first and second coating layers includes one or more materials selected from the group consisting of Ag, Au, Zn, Sn, In, Al, Bi, Sb, Ge, and Te. 
     
     
       25. The multilayer capacitor of  claim 20 , wherein the body further includes a second dielectric layer and third and fourth internal electrodes connected to each other by the second dielectric layer,
 the first and second external electrodes are connected to the third and fourth internal electrodes, respectively, 
 a thickness of the fourth internal electrode is less than a thickness of the third internal electrode, and 
 the third internal electrode is made of the first conductive paste and the fourth internal electrode is made of the second conductive paste. 
 
     
     
       26. The multilayer capacitor of  claim 20 , wherein the body further includes a second dielectric layer and third and fourth internal electrodes connected to each other by the second dielectric layer,
 the first and second external electrodes are connected to the third and fourth internal electrodes, respectively, 
 a thickness of the third internal electrode is less than a thickness of the fourth internal electrode, and 
 the third internal electrode is made of the second conductive paste and the fourth internal electrode is made of the first conductive paste.